Method op making shredders



Feb. 26; 1935. A H', IXON r R 19,477

METHOD OF MAKING SHREDDERS Original Filed Oct. 21, 1929 Fiber/#172180,

INVENTOR 5 ATTORNEY Reissuecl Feb. 26, 1935 UNITEDV'STATES METHOD OFMAKING SHREDDERS Albert H. Dixon, Seattle, Wash., and Thomas S.

Robson, Victoria, British Columbia, and Ferdi- 1 nand A. Henschell,Vancouver, British Columbia, Canada, assignors to Rapid ManufacturingCo. Inc., Seattle, Washington Wash., a corporation of Original No.1,768,462, dated June 24, 1930, Serial No. 401,268, October 21, 1929.Application for reissue June 20, 1932, Serial No. 618,346

5 Claims.

The general object of the invention is to provide a method for formingteeth on sheets of metal, wherein the operation of forming the teethwill give them a beveled cutting edge making unnecessary the preparationof such edge by a subsequent sharpening operation.

This invention also consists in certain other features of constructionand in the combination and arrangement of the several parts, to behereinafter fully described, illustrated in the accompanying drawing andspecifically pointed out in the appended claims.

In describing the invention in detail, reference is had to theaccompanying drawing wherein like characters denote like orcorresponding parts throughout the several views, and in which:

Figure 1 is a sectional view showing the first part of the punchingoperation for forming a hole and beveling the cutting edge of a tooth tobe formed on a member.

Figure 2 is a similar view showing the completion of the operation.

Figure 3 is a View of thehole and beveled part formed by the beforementioned operation.

Figure 4 is a sectional view showing how the metal is pressed adjacentthe hole previously formed therein to form the tooth.

This invention relates primarily to the formation of the teeth of ashredder device, such as that forming the subject matter of Patent No.1,768,463, though, of course, the invention is not limited to this use.The first step of forming each tooth in the metal plate A, which may bethe body of the shredder, consists in placing the metal on a female die1 having an opening 2 therein, the upper part of which is formed with abeveled enlargement 3. Then a punch 4, having a cutting edge 5, isforced through the metal into the opening 2, as shown in Figures 1 and2. This operation initially shears the metal for a part of the perimeterof the scrap to be removed and thereafter depresses the stock at theunsheared part of the scrap, the depressed portion being forced into thebeveled enlargement in which, when it is firmly seated therein, furthermovement of the punch completes the shearing and the scrap is forcedthrough the die opening. By reason of depressing the stock into theenlargement, the upper face becomes disposed at an acute angle to theaxis of the punch prior to completing the shearing operation and theedge formed when the scrap is completely severed is at a acute angle tothe face of the blank or plate, this acute edge becoming the cuttingedge when the blank is subjected to the operation of the forming dies.The blank is then placed on the female forming die 6 having the recess 7therein which gradually increases in depth from the point 8 to thestraight wall 9, the recess being of curved shape in cross section. Themale die 10 which is of the same conformation as the recess thendepresses the stock into the latter, defleeting it from the plane of theplate and completing the formation of the tooth, the previously formedacute edge of which is then disposed at a more acute angle to the platethan formerly, as shown in Figure 4. Thus a raised portion constitutinga tooth is formed on the metal sheet and has a sharp beveled cuttingedge spanning the opening from which the scrap was removed.

It is thought from the foregoing description that the advantages andnovel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction andin the combination and arrangement of the several parts, provided thatsuch changes fall within the scope of the appended claims.

The invention having been described, what is claimed as new and usefulis:

1. The herein described method of forming teeth on a sheet of materialconsisting in punching a hole in the sheet and bending a portion of thesheet adjacent the hole at an angle so that that part of the wall of thehole in said bent portion is beveled, then'pressing the sheet at oneside of the hole outwardly beyond the plane of the sheet whereby thebent portion is further bent and forms part ofthe outwardly bent portionso as to produce a tooth having a beveled edge.

2. The herein described method of forming teeth in a sheet of materialconsisting in placing the sheet on a die having an opening therein, theupper end of which is formed with a beveled enlargement and thenpressing the punching die through the metal into the opening, whereby aportion of the metal will be bent against the beveled enlargement andthen the metal cut to provide an opening, the wall of which that iscontained in the bent part being beveled and then placing the sheetbetween two other dies to press the metal at one side of the openinginto a tooth, the cutting edge of which is formed by the beforementioned beveled wall of the opening.

3. The method of forming cutting elements in sheet material whichcomprises partially shearing the sheet, deflecting from the plane of thesheet a small area of the material still connected with the scrap, thencompleting the severing of tion and adjacent material of the sheet tothrow the edge from which the scrap was finally severed to a pronouncedinclination to the plane of the sheet.

4. The methodof formingcutting elements in sheet material whichcomprises partially severing the sheet, deflecting from the plane of thesheet the material adjacent the severed portion but remaining connectedwith the scrap, then completing the severance of the scrap'to' form abeveled edge on the deflected portion; then depressing from the planeofthe sheet the de flected portion and adjacent material to throw thebeveled edge at a pronounced mummies to the plane of the sheet.

5. The method of forming cutting elements in sheet material whichcomprises slitting the sheet, bulging a small area of the sheet at oneside of the slitwith the slit as one'o'f the'boundaiy lines ofthe'bulg'e, and finally shearing the scrap from the bulged portion toleave an opening in the sheet and form a beveled edge becoming thecutting edge when the blank is subjected to a further forming operation.

